The present invention relates to apparatus and methods for measuring weight of an object in a seat and apparatus and methods for adjusting stiffness of the seat.
The present invention also relates to methods and apparatus for ascertaining the identity of objects in a vehicle and methods for adjusting components of or in the vehicle based on the identity of the objects.
The present invention also relates to apparatus and methods for adjusting a vehicle component, system or subsystem in which the occupancy of a seat, also referred to as the xe2x80x9cseated statexe2x80x9d herein, is evaluated using sensors and the component, system or subsystem may then be adjusted based on the evaluated occupancy thereof. The vehicle component, system or subsystem, hereinafter referred to simply as a component, may be any adjustable component of the vehicle including, but not limited to, the bottom portion and backrest of the seat, the rear view and side mirrors, the brake, clutch and accelerator pedals, the steering wheel, the steering column, a seat armrest, a cup holder, the mounting unit for a cellular telephone or another communications or computing device and the visors. Further, the component may be a system such an as airbag system, the deployment or suppression of which is controlled based on the seated-state of the seat. The component may also be an adjustable portion of a system the operation of which might be advantageously adjusted based on the seated-state of the seat, such as a device for regulating the inflation or deflation of an airbag that is associated with an airbag system.
The present invention also relates to apparatus and method for automatically adjusting a vehicle component to a selected or optimum position for an occupant of a seat based on two measured morphological characteristics of the occupant. Morphological characteristics include the weight of the occupant, the height of the occupant measured from the seat, the length of the occupant""s arms, the length of the occupant""s legs, the occupant""s head diameter and the inclination of the occupant""s back relative to the seat bottom. Other morphological characteristics are also envisioned for use in the invention.
Automobiles equipped with airbags are well known in the prior art. In such airbag systems, the car crash is sensed and the airbags rapidly inflated thereby ensuring the safety of an occupation in a car crash. Many lives have now been saved by such airbag systems. However, depending on the seated state of an occupant, there are cases where the life of the occupant cannot be saved even by present airbag systems. For example, when a passenger is seated on the front passenger seat in a position other than a forward facing, normal state, e.g., when the passenger is out of position and near the deployment door of the airbag, there will be cases when the occupant will be seriously injured or even killed by the deployment of the airbag.
Also, sometimes a child seat is placed on the passenger seat in a rear facing position and there are cases where a child sitting in such a seat has been seriously injured or killed by the deployment of the airbag.
Furthermore, in the case of a vacant seat, there is no need to deploy an airbag, and in such a case, deploying the airbag is undesirable due to a high replacement cost and possible release of toxic gases into the passenger compartment. Nevertheless, most airbag systems will deploy the airbag in a vehicle crash even if the seat is unoccupied.
For these reasons, there has been proposed a seated-state detecting unit such as disclosed in the following U.S. Patents and Patent applications, which are included herein by reference, assigned to the current assignee of the present application: Breed et al. (U.S. Pat. No. 5,563,462); Breed et al (U.S. Pat. No. 5,829,782); Breed et al (U.S. Pat. No. 5,822,707): Breed et al (U.S. Pat. No. 5,694,320); Breed et al (U.S. Pat. No. 5,748,473); and Varga et al (U.S. Pat. No. 5,943,295). Typically, in some of these designs four sets of sensors are installed at four points in a vehicle passenger compartment for transmitting ultrasonic or electromagnetic waves toward the passenger or driver""s seat and receiving the reflected waves. Using appropriate hardware and software, the approximate configuration of the occupancy of either the passenger or driver seat can be determined thereby identifying and categorizing the occupancy of the relevant seat.
However, in the aforementioned literature using ultrasonics, the pattern of reflected ultrasonic waves from an adult occupant who may be out of position is sometimes similar to the pattern of reflected waves from a rear facing child seat. Also, it is sometimes difficult to discriminate the wave pattern of a normally seated child with the seat in a rear facing position from an empty seat with the seat in a more forward position. In other cases, the reflected wave pattern from a thin slouching adult with raised knees can be similar to that from a rear facing child seat. In still other cases, the reflected pattern from a passenger seat which is in a forward position can be similar to the reflected wave pattern from a seat containing a forward facing child seat or a child sitting on the passenger seat. In each of these cases, the prior art ultrasonic systems can suppress the deployment of an airbag when deployment is desired or, alternately, can enable deployment when deployment is not desired.
If the discrimination between these cases can be improved, then the reliability of the seated-state detecting unit can be improved and more people saved from death or serious injury. In addition, the unnecessary deployment of an airbag can be prevented.
The adjustment of an automobile seat occupied by a driver of the vehicle is now accomplished by the use of either electrical switches and motors or by mechanical levers. As a result, the driver""s seat is rarely placed at the proper driving position which is defined as the seat location which places the eyes of the driver in the so-called xe2x80x9ceye ellipsexe2x80x9d and permits him or her to comfortably reach the pedals and steering wheel. The xe2x80x9ceye ellipsexe2x80x9d is the optimum eye position relative to the windshield and rear view mirror of the vehicle.
The eye ellipse, which is actually an ellipsoid, is rarely achieved by the actions of the driver for a variety of reasons. One specific reason is the poor design of most seat adjustment systems particularly the so-called xe2x80x9c4-way-seatxe2x80x9d. It is known that there are three degrees of freedom of a seat bottom, namely vertical, longitudinal, and rotation about the lateral or pitch axis. The 4-way-seat provides four motions to control the seat: (1). raising or lowering the front of the seat, (2) raising or lowering the back of the seat, (3) raising or lowering the entire seat, (4) moving the seat fore and aft. Such a seat adjustment system causes confusion since there are four control motions for three degrees of freedom. As a result, vehicle occupants are easily frustrated by such events as when the control to raise the seat is exercised, the seat not only is raised but is also rotated. Occupants thus find it difficult to place the seat in the optimum location using this system and frequently give up trying leaving the seat in an improper driving position.
Many vehicles today are equipped with a lumbar support system that is never used by most occupants. One reason is that the lumbar support cannot be preset since the shape of the lumbar for different occupants differs significantly, i.e., a tall person has significantly different lumbar support requirements than a short person. Without knowledge of the size of the occupant, the lumbar support cannot be automatically adjusted.
As discussed in the above referenced ""320 patent, in approximately 95% of the cases where an occupant suffers a whiplash injury, the headrest is not properly located to protect him or her in a rear impact collision. Also, the stiffness and damping characteristics of a seat are fixed and no attempt is made in any production vehicle to adjust the stiffness and damping of the seat in relation to the size or weight of an occupant, or to the environmental conditions such as road roughness. All of these adjustments, if they are to be done automatically, require knowledge of the morphology of the seat occupant.
Systems are now being used to attempt to identify the vehicle occupant based on a coded key or other object carried by the occupant. This requires special sensors within the vehicle to recognize the coded object. Also, the system only works if the coded object is used by the particular person for whom the vehicle was programmed. If the vehicle is used by a son or daughter, for example, who use their mother""s key then the wrong seat adjustments are made. Also, these systems preserve the choice of seat position without any regard for the correctness of the seat position. With the problems associated with the 4-way seats, it is unlikely that the occupant ever properly adjusts the seat. Therefore, the error will be repeated every time the occupant uses the vehicle.
Moreover, these coded systems are a crude attempt to identify the occupant. An improvement can be made if the morphological characteristics of the occupant can be measured as described below. Such measurements can be made of the height and weight, for example, and used not only to adjust a vehicular component to a proper position but also to remember that position, as fine tuned by the occupant, for re-positioning the component the next time the occupant occupies the seat. For the purposes herein, a morphological characteristic will mean any measurable property of a human such as height, weight, leg or arm length, head diameter etc.
As discussed more fully below, in a preferred implementation, once at least one and preferably two of the morphological characteristics of a driver are determined, e.g., by measuring his or her height and weight, the component such as the seat can be adjusted and other features or components can be incorporated into the system including, for example, the automatic adjustment of the rear view and/or side mirrors based on seat position and occupant height. In addition, a determination of an out-of-position occupant can be made and based thereon, airbag deployment suppressed if the occupant is more likely to be injured by the airbag than by the accident without the protection of the airbag. Furthermore, the characteristics of the airbag, including the amount of gas produced by the inflator and the size of the airbag exit orifices to control the pressure in the airbag, can be adjusted to provide better protection for small lightweight occupants as well as large, heavy people. Even the direction of the airbag deployment can, in some cases, be controlled.
Still other features or components can now be adjusted based on the measured occupant morphology as well as the fact that the occupant can now be identified. Some of these features or components include the adjustment of seat armrest, cup holder, steering wheel (angle and telescoping), position of the pedals, phone location and for that matter the adjustment of all things in the vehicle that a person must reach or interact with. Some items that depend on personal preferences can also be automatically adjusted including the radio station, temperature, ride and others.
Most, if not all, of the problems discussed above are difficult to solve or unsolvable using conventional technology.
The use of pattern recognition, or more particularly how it is used, is important to some aspects of the instant invention. In the above-cited prior art, except in that assigned to the current assignee of the instant invention, pattern recognition which is based on training, as exemplified through the use of neural networks, is not mentioned for use in monitoring the interior passenger compartment or exterior environments of the vehicle or in determining the""seated state of a vehicle seat.
xe2x80x9cPattern recognitionxe2x80x9d as used herein will: generally mean any system which processes a signal that is generated by an object (e.g., representative of a pattern of returned or received impulses, waves or other physical property specific to and/or characteristic of and/or representative of that object) or is modified by interacting with an object, in order to determine to which one of a set of classes that the object belongs. Such a system might determine only that the object is or is not a member of one specified class, or it might attempt to assign the object to one of a larger set of specified classes, or find that it is not a member of any of the classes in the set. The signals processed are generally a series of electrical signals coming from transducers that are sensitive to acoustic (ultrasonic) or electromagnetic radiation (e.g., visible light, infrared radiation, radar, or any other frequency), although other sources of information are frequently included.
A trainable or a trained pattern recognition system as used herein generally means a pattern recognition system which is taught to recognize various patterns constituted within the signals by subjecting the system to a variety of examples. The most successful such system is the neural network. Thus, to generate the pattern recognition algorithm, test data is first obtained which constitutes a plurality of sets of returned waves, or wave patterns, from an object (or from the space in which the object will be situated in the passenger compartment, i.e., the space above the seat) and an indication of the identity of that object, (e.g., a number of different objects are tested to obtain the unique wave patterns from each object). As such, the algorithm is generated, and stored in a computer processor, and which can later be applied to provide the identity of an object based on the wave pattern being received during use by a receiver connected to the processor and other information. For the purposes here, the identity of an object sometimes applies to not only the object itself but also to its location and/or orientation in the passenger compartment. For example, a rear facing child seat is a different object than a forward facing child seat and an out-of-position adult is a different object than a normally seated adult.
Other means of pattern recognition exist where the training is done by the researcher including Fuzzy Logic and Sensor Fusion systems.
To xe2x80x9cidentifyxe2x80x9d as used herein will generally mean to determine that the object belongs to a particular set or class. The class may be one containing, for example, all rear facing child seats, one containing all human occupants, or all human occupants not sitting in a rear facing child seat depending on the purpose of the system. In the case where a particular person is to be recognized, the set or class will contain only a single clement, i.e., the person to be recognized.
To xe2x80x9cascertain the identity ofxe2x80x9d as used herein with reference to an object will generally mean to determine the type or nature of the object (obtain information as to what the object is), i.e., that the object is an adult, an occupied rear facing child seat, an occupied front facing child seat, an unoccupied rear facing child seat, an unoccupied front facing child seat, a child, a dog, a bag of groceries, etc.
An xe2x80x9cobjectxe2x80x9d or xe2x80x9coccupying itemxe2x80x9d of a seat; may be a living occupant such as a human or a dog, another living organism such as a plant, or an inanimate object such as a box or bag of groceries or an empty child seat.
xe2x80x9cOut-of-positionxe2x80x9d as used for an occupant will generally means that the occupant, either the driver or a passenger, is sufficiently close to the occupant. protection apparatus (airbag) prior to deployment that he or she is likely to be more seriously injured by the deployment event itself than by the accident. It may also mean that the occupant is not positioned appropriately in order to attain the beneficial, restraining effects of the deployment of the airbag. As for the occupant being too close to the airbag, this typically occurs when the occupant""s head or chest is closer than some distance such as about 5 inches from the deployment door of the airbag module. The actual distance value where airbag deployment should be suppressed depends on the design of the airbag module and is typically farther for the passenger airbag than for the driver airbag.
xe2x80x9cTransducerxe2x80x9d as used herein will generally mean the combination of a transmitter and a receiver. In some cases, the same device will serve both as the transmitter and receiver while in others two separate devices adjacent to each other will be used. In some cases, a transmitter is not used and in such cases transducer will mean only a receiver. Transducers include, for example, capacitive, inductive, ultrasonic, electromagnetic (antenna, CCD, CMOS arrays), weight measuring or sensing devices.
xe2x80x9cAdaptationxe2x80x9d as used here represents the method by which a particular occupant sensing system is designed and arranged for a particular vehicle model. It includes such things as the process by which the number, kind and location of various transducers is determined. For pattern recognition systems, it includes the process by which the pattern recognition system is taught to recognize the desired patterns. In this connection, it will usually include (1) the method of training, (2) the makeup of the databases used for training, testing and validating the particular system, or, in the case of a neural network, the particular network architecture chosen, (3) the process by which environmental influences are incorporated into the system, and (4) any process for determining the pre-processing of the data or the post processing of the results of the pattern recognition system. The above list is illustrative and not exhaustive. Basically, adaptation includes all of the steps that are undertaken to adapt transducers and other sources of information to a particular vehicle to create the system that accurately identifies and determines the location of ail occupant or other object in a vehicle.
Accordingly, it is a principal object of the present invention to provide new and improved vehicular component adjustment apparatus and methods which evaluate the occupancy of the seat based at least in part on a measurement of the weight applied onto the seat and adjust the location and/or orientation relative to the occupant and/or operation of a part of the component or the component in its entirety based on the evaluated occupancy of the seat.
It is another object of the present invention to provide new and improved adjustment apparatus and methods that evaluate the occupancy of the seat based at least in part on a measurement of the weight applied onto the seat and adjust the location and/or orientation relative to the occupant and/or operation of a part of the component or the component in its entirety based on the evaluated occupancy of the seat and on a measurement of the approximate height of the occupant and/or a measurement of the occupant""s weight.
It is another object of the present invention to provide new and improved adjustment apparatus and methods that evaluate the occupancy of the seat by a combination of wave sensors and additional sensors, such as a weight sensor, and adjust the location and/or orientation relative to the occupant and/or operation of a part of the component or the component in its entirety based on the evaluated occupancy of the seat.
It is another object of the present invention: to provide new and improved adjustment apparatus and methods that reliably discriminate between a normally seated passenger and a forward facing child seat, between an abnormally seated passenger and a rear facing child seat, and whether or not the seat is empty and adjust the location and/or orientation relative to the occupant and/or operation of a part of the component or the component in its entirety based thereon.
It is another object of the present invention to provide new and improved adjustment apparatus and methods that evaluate the occupancy of the seat based at least in part on the weight applied onto the seat without the problems mentioned above.
Additional objects and advantages of some :of the disclosed inventions include:
1. To provide a system for passively and automatically adjusting the position of a vehicle component to a near optimum location based on a measure of the weight and/or size of an occupant.
2. To provide a system for recognizing a particular occupant of a vehicle and thereafter adjusting various components of the vehicle in accordance with the preferences of the recognized occupant.
3. To provide systems for approximately locating the eyes of a vehicle driver to thereby permit the placement of the driver""s eyes at a particular location in the vehicle.
4. To provide a pattern recognition system to permit more accurate location of an occupant""s head and the parts thereof and to use this information to adjust a vehicle component.
5. To provide a method of determining whether a seat is occupied and, if not, leaving the seat at a neutral position.
6. To provide a system for automatically adjusting the position of various components of the vehicle to permit safer and more effective operation of the vehicle including the location of the pedals and steering wheel.
7. To determine whether an occupant is out-of-position relative to the airbag and if so, to suppress deployment of the airbag in a situation in which the airbag would otherwise be deployed.
8. To adjust the flow of gas into and out of the airbag based on the morphology and position of the occupant to improve the performance of the airbag in reducing occupant injury.
9. To provide a system where the morphological characteristics of an occupant are measured by sensors located within the seat.
Further objects of the present invention will become apparent from the following discussion of the preferred embodiments of the invention.
One embodiment of a weight sensor and method for determining the weight of an occupant of a seat, which may be used in the methods and apparatus for adjusting a vehicle component and identifying an occupant of a seat, comprises a bladder having at least one chamber adapted to be arranged in a seat portion of the seat, and at least one transducer for measuring the pressure in a respective chamber. The bladder may comprises a plurality of chambers, each adapted to be arranged at a different location in the seat portion of the seat. Thus, it is possible to determine the weight distribution of the occupant using this weight sensor with several transducers whereby each transducer is associated with one chamber and the weight distribution of the occupant is obtained from the pressure measurements of the transducers. The position of the occupant and the center of gravity of the occupant can also be determined based on the weight distribution.
A novel occupant position sensor for a vehicle, for determining the position of the occupant, comprises a weight sensor for determining the weight of an occupant of a seat as described immediately above and processor means for receiving the determined weight of the occupant from the weight sensor and determining the position of the occupant based at least on part on the determined weight of the occupant. The position of the occupant could also be determined based in part on waves received from the space above the seat, data from seat position sensors, reclining angle sensors, etc.
In an apparatus for adjusting the stiffness of a seat in a vehicle, an outer container is arranged in a bottom portion of the seat and at least one inner container is arranged at least partially in an interior of the outer container. The inner and outer containers are in flow communication with each other through a variable flow passage. Insertion means, e.g., an air compressor, are provided for directing a medium into the outer container and monitoring means, e.g., a pressure transducer, measuring the pressure in the outer container. A control circuit is coupled to the medium insertion means and the monitoring means for regulating flow of medium into the outer container via the medium insertion means until the pressure in the outer container as measured by the monitoring means is indicative of a desired stiffness for the seat. The control circuit may also be arranged to adjust the flow passage to thereby control flow of medium between the inner and outer containers and thus damping of the seat. The flow passage may be an orifice in a peripheral wall of the inner container.
A method for adjusting the stiffness of a seat in a vehicle comprises the steps of arranging an outer container in a bottom portion of the seat, arranging an inner container at least partially in an interior of the outer container, coupling interior volumes of the inner and outer containers through a variable flow passage, measuring the pressure in the outer container, and introducing medium into the outer container until the measured pressure in the outer container is indicative of a desired stiffness for the seat.
One embodiment of a seated-state detecting unit and method for ascertaining the identity of an object in a seat in a passenger compartment of a vehicle in accordance with the invention comprises a wave-receiving sensor arranged to receive waves from a space above the seat and generate an output representative of the received waves, weight measuring means associated with the seat for measuring the weight applied onto the seat (such as described above) and generating an output representative of the measured weight applied onto the seat, and processor means for receiving the outputs from the wave-receiving sensor and the weight measuring means and for evaluating the seated-state of the seat based thereon to determine whether the seat is occupied by an object and when the seat is occupied by an object, to ascertain the identity of the object in the seat based on the outputs from the wave-receiving sensor and the weight measuring means. If necessary depending on the type of wave-receiving sensor, waves are transmitted into the passenger compartment toward the seat to enable reception of the same by the wave-receiving sensor. The wave-receiving sensor may be an ultrasonic sensor structured and arranged to receive ultrasonic waves, an electromagnetic sensor structured and arranged to receive electromagnetic waves or a capacitive sensor for generating an output representative of the object based on the object""s dielectric properties. The processor means may comprise a microcomputer into which a function correlating the outputs from the wave-receiving sensor and the weight measuring means and the seated-state of the seat is incorporated or a neural network which generates a function correlating the outputs from the wave-receiving sensor and the weight measuring means and the seated-state of the seat and executes the function using the outputs from the wave-receiving sensor and the weight measuring means as input to determine the seated-state of the seat.
Additional sensors may be provided to enhance the procedure for ascertaining the identity of the object. Such sensors, e.g., a seat position detecting sensor, reclining angle detecting sensor, heartbeat or other animal life state sensor, motion sensor, etc., provide output directly or indirectly related to the object which is considered by the processor means when evaluating the seated-state of the seat.
The weight measuring means may comprise one or more weight sensors, possibly arranged in connection with the seat, for measuring the force or pressure applied onto at least a portion of the seat. In the alternative, a bladder having at least one chamber may be arranged in a seat portion of the seat for measuring the force or pressure applied onto at least a portion of the seat.
The adjustment system and method for adjusting a component of a vehicle based on the presence of an object ill of a seat include a wave-receiving. sensor as described immediately above, weight measuring means as described above, adjustment means arranged in connection with the component for adjusting the component, and processor means for receiving the outputs from the wave-receiving sensor and the weight measuring means and for evaluating the seated-state of the seat based thereon to determine whether the seat is occupied by an object and when the seat is occupied by an object, to ascertain the identity of the object in the seat based on the outputs from the wave-receiving sensor and the weight measuring means. The processor means also direct the adjustment means to adjust the component based at least on the identity of the object.
If the component is an airbag system, the processor means may be designed to direct the adjustment means to suppress deployment of the airbag when the object is identified as an object for which deployment of the airbag is unnecessary or would be more likely to harm the object than protect the object, depowered the deployment of the airbag or affect any deployment parameter, e.g., the inflation rate, deflation rate, number of deploying airbags, deployment rate, etc. Thus, the component may be a valve for regulating the flow of gas into or out of an airbag.
Another embodiment of the apparatus in accordance with invention includes a first measuring system for measuring a first morphological characteristic of the occupying item of the seat and a second measuring system for measuring a second morphological characteristic of the occupying item. Morphological characteristic include the weight of the occupying item, the height of the occupying item from the bottom portion of the seat and if the occupying item is a human, the arm length, head diameter leg length and dielectric properties. The apparatus also includes processor means for receiving the output of the first and second measuring systems and for processing the outputs to evaluate a seated-state based on the outputs. The measuring systems described herein, as well as any other conventional measuring systems, may be used in the invention to measure the morphological characteristics of the occupying item.
One preferred embodiment of an adjustment system in accordance with the invention includes a plurality of wave-receiving sensors for receiving waves from the seat and its contents, if any, and one or more weight sensors for detecting weight of an occupant in the seat or an absence of weight applied onto the seat indicative of a vacant seat. The apparatus also includes processor means for receiving the output of the wave-receiving sensors and the weight sensor(s) and for processing the outputs to evaluate a seated-state based on the outputs. The processor means then adjust a part of the component or the component in its entirety based at least on the evaluation of the seated-state of the seat. The wave-receiving sensors may be ultrasonic sensors, optical sensors or electromagnetic sensors operating at other than optical frequencies. If the wave-receiving sensors are ultrasonic or optical sensors, then they may also include transmitter means for transmitting ultrasonic or optical waves toward the seat. For the purposes herein, optical is used to include the infrared, visible and ultraviolet parts of the electromagnetic spectrum.
If the component is a seat, the system includes power means for moving at least one portion of the seat relative to the passenger compartment and control means connected to the power means for controlling the power means to move the portion(s) of the seat. In this case, the processor means may direct the control means to affect the power means based at least in part on the evaluation of the seated-state of the seat. With respect to the direction or regulation of the control means by the processor means, this may take the form of a regulation signal to the control means that no seat adjustment is needed, e.g., if the seat is occupied by a bag of groceries or a child seat in a rear or forward-facing position as determined by the evaluation of the output from the ultrasonic or optical and weight sensors. On the other hand, if the processor means determines that the seat is occupied by an adult or child for which adjustment of the seat is beneficial or desired, then the processor means may direct the control means to affect the power means accordingly. For example, if a child is detected on the seat, the processor means may be designed to lower the headrest.
In certain embodiments, the apparatus may include one or more sensors each of which measures a morphological characteristic of the occupying item of the seat, e.g., the height, weight or dielectric properties of the occupying item, and the processor means are arranged to obtain the input from these sensors and adjust the component accordingly. Thus, once the processor means evaluates the occupancy of the seat and determines that the occupancy is by an adult or child, then the processor means may additionally use either the obtained weight measurement or conduct additional measurements of morphological characteristics of the adult or child occupant and adjust the component accordingly. The processor means may be a single microprocessor for performing all of the functions described above. In the alternative, one microprocessor may be used for evaluating the occupancy of the seat and another for adjusting the component.
The processor means may comprise an evaluation circuit implemented in hardware as an electronic circuit or in software as a computer program.
In certain embodiments, a correlation function or state between the output of the various sensors and the desired result (i.e., seat occupancy identification and categorization) is determined, e.g., by a neural network that may be implemented in hardware as a neural computer or in software as a computer program. The correlation function or state that is determined by employing this neural network may also be contained in a microcomputer. In this case, the microcomputer can be employed as an evaluation circuit. The word circuit herein will be used to mean both an electronic circuit and the functional equivalent implemented on a microcomputer using software.
In enhanced embodiments, a heartbeat or animal life state sensor may be provided for detecting the heartbeat of the occupant if present or animal life state and generating an output representative thereof. The processor means additionally receives this output and evaluates the seated-state of the seat based in part thereon. In addition to or instead of such a heartbeat or animal life state sensor, a capacitive sensor and/or a motion sensor may be provided. The capacitive sensor is a particular implementation of an electromagnetic wave sensor that detects the presence of the occupant and generates an output representative of the presence of the occupant based on its dielectric properties. The motion sensor detects movement of the occupant and generates an output representative thereof. These outputs are provided to the processor means for possible use in the evaluation of the seated-state of the seat.
The portion of the apparatus which includes the ultrasonic, optical or non-optical electromagnetic sensors, weight measuring means and processor means which evaluate the occupancy of the seat based on the measured weight of the seat and its contents and the returned waves from the ultrasonic, optical or non-optical electromagnetic sensors may be considered to constitute a seated-state detecting unit.
The seated-state detecting unit may further: comprise a seat position-detecting sensor. This sensor determines the position of the seat in the forward and aft direction. In this case, the evaluation circuit evaluates the seated-state, based on a correlation function obtain from outputs of the ultrasonic sensors. an output of the one or more weight sensors, and an output of the seat position detecting sensor. With this structure, there is the advantage that the identification between the flat configuration of a detected surface in a state where a passenger is not sitting in the seat and the flat configuration of a detected surface which is detected when a seat is slid backwards by the amount of the thickness of a passenger, that is, of identification of whether a passenger seat is vacant or occupied by a passenger, can be reliably performed.
Furthermore, the seated-state detecting unit may also comprise a seat back reclining angle detecting sensor, and the evaluation circuit may also evaluate the seated-state based on a correlation function obtained from outputs of the ultrasonic, optical or non-optical electromagnetic sensors, an output of the weight sensor(s), and an output of the seat back reclining angle detecting sensor. In this case, if the tilted angle information of the back portion of the seat is added as evaluation information for the seated-state, identification can be clearly performed between the flat configuration of a surface detected when a passenger is in a slightly slouching state and the configuration of a surface detected when the back portion of a seat is slightly tilted forward and similar difficult-to-discriminate cases. This embodiment may even be combined with the output from a seat position-detecting sensor to further enhance the evaluation circuit.
Moreover, the seated-state detecting unit may further comprise a comparison circuit for comparing the output of the weight sensor(s) with a reference value. In this case, the evaluation circuit identifies an adult and a child based on the reference value.
Preferably, the seated-state detecting unit comprises: a plurality of ultrasonic, optical or non-optical electromagnetic sensors for transmitting ultrasonic or electromagnetic waves toward a seat and receiving reflected waves from the seat; one or more weight sensors for detecting weight of a passenger in the seat; a seat position detecting sensor; a reclining angle detecting sensor; and a neural network to which outputs of the ultrasonic or electromagnetic sensors. and the weight sensor(s), an output of the seat position detecting sensor, and an output of the reclining angle detecting sensor are inputted and which evaluates several kinds of seated-states, based on a correlation function obtained from the outputs.
The kinds of seated-states that can be evaluated and categorized by the neural network include the following categories, among others, (i) a normally seated passenger and a forward facing child seat, (ii) an abnormally seated passenger and a rear-facing child seat, and (iii) a vacant seat.
The seated-state detecting unit may further comprise a comparison circuit for comparing the output of the weight sensor(s) with a reference value and a gate circuit to which the evaluation signal and a comparison signal from the comparison circuit are input. This gate circuit, which may be implemented in software or hardware, outputs signals which evaluates several kinds of seated-states. These kinds of seated-states can include a (i) normally seated passenger, (ii) a forward facing child seat, (iii) an abnormally seated passenger, (iv) a rear facing child seat, land (v) a vacant seat. With this arrangement, the identification between a normally seated passenger and a forward facing child seat, the identification between an abnormally seated passenger and a rear facing child seat, and the identification of a vacant seat can be more reliably performed.
The outputs of the ultrasonic or electromagnetic sensors, the output of the weight sensor(s), the outputs of the seat position detecting sensor, and the outputs of the reclining angle detecting sensor are inputted to the neural network or other pattern recognition circuit, and the neural network determines the correlation function, based on training thereof during a training phase. The correlation function is then typically implemented in or incorporated into a microcomputer. For the purposes herein, neural network will be used to include both a single neural network, a plurality of neural networks (including serial and parallel modular neural networks), and other similar pattern recognition circuits or algorithms and combinations thereof.
For the ultrasonic implementation, to provide the input from the ultrasonic sensors to the neural network (circuit), it is preferable that an initial reflected wave portion and a last reflected wave portion are removed from each of the reflected waves of the ultrasonic or electromagnetic sensors and then the output data is processed. The neural network determine""s the correlation function by performing a weighting process, based on output data from the plurality of ultrasonic sensors, output data from the weight sensor(s), output data from the seat position detecting sensor if present, and/or on output data from the reclining angle detecting sensor if present.
With this arrangement, the portions of the reflected ultrasonic wave that do not contain useful information are removed from the analysis and the presence and recognition of an object on the passenger seat can be more accurately performed. Similar data pruning takes place with electromagnetic sensors.
In a disclosed method for determining the occupancy of a seat in a passenger compartment of a vehicle in accordance with the invention, waves such as ultrasonic or electromagnetic waves are transmitted into the passenger compartment toward the seat, reflected or modified waves from the passenger compartment are received by a component which then generates an output representative thereof, the weight applied onto the seat is measured and an output is generated representative thereof and then the seated-state of the seat is evaluated based on the outputs from the sensors and the weight measuring means.
The evaluation the seated-state of the seat may be accomplished by generating a function correlating the outputs representative of the received waves and the measured weight and the seated-state of the seat, and incorporating the correlation function into a microcomputer. In the alternative, it is possible to generate a function correlating the outputs representative of the received waves and the measured weight and the seated-state of the seat in a neural network (circuit), and execute the function using the outputs representative of the received waves and the measured weight as input into the neural network.
To enhance the seated-state determination, the position of a seat is measured and an output representative thereof is generated, and then the seated-state of the seat is evaluated based on the outputs representative of the received reflected waves, the measured weight and the measured seat position. In addition to or instead of measuring the seat position, it is possible to measure the reclining angle of the seat, i.e., the angle between the seat portion and the back portion of the seat, and generate an output representative thereof, and then evaluate the seated-state of the seat based on the outputs representative of the received waves, the measured weight and the measured reclining angle of the seat (and seat position, if measured).
Furthermore, the output representative of the measured weight may be compared with a reference value, and the occupying object of the seat identified, e.g., as an adult or a child, based on the comparison of the measured weight with the reference value.
In additional embodiments, the present invention involves the measurement of one or more morphological characteristics of a vehicle occupant and the use of these measurements to classify the occupant as to size and weight, and then to use this classification to position a vehicle component, such as the seat, to a near optimum position for that class of occupant. Additional information concerning occupant preferences can also be associated with the occupant class so that when a person belonging to that particular class occupies the vehicle, the preferences associated with that class are implemented. These preferences and associated component adjustments include the seat location after it has been manually adjusted away from the position chosen initially by the system, the mirror location, temperature, radio station, steering wheel and steering column positions, pedal positions etc. The preferred morphological characteristics used are the occupant height from the vehicle seat and weight of the occupant. The height is determined by sensors, usually ultrasonic or electromagnetic, located in the headrest, headliner or another convenient location. The weight is determined by one of a variety of technologies that measure either pressure on or displacement of the vehicle seat or the force in the seat supporting structure.
The preferred system of measuring weight on the occupancy seat is disclosed in co-pending U.S. patent application Ser. No. 09/193,209, filed Nov. 17, 1988, which is included herein by reference. This patent application describes a weighing system based on the force or strain imparted to the seat structure by the seat occupant. Preferably, the invention is implemented by placing strain gage sensors on the main supporting structures of the vehicle seat. An alternate approach, which will be described in more detail below, utilizes a bladder, which can have one or more chambers, wherein each chamber has a pressure sensor capable of measuring the pressure of the fluid in the chamber. The chambers may be filled with air or other gas, liquid or a jell. A single chamber is sufficient if the overall weight of the occupant is desired. If the weight distribution of the occupant is required, then multiple chambers become necessary. If the bladder is properly designed, then the total weight of the occupant can be determined by summing the forces on the individual chambers (pressure x area). One example of the system will be described in more detail below.